Maher began his career in the Parks department as an Urban Park Ranger.[7] Additionally, Maher worked in a spectrum of different positions with-in the department from manager at Coney Island, to inspector at Shea Stadium, to Yankee Stadium, to the 79th Street Boat Basin, and Randall's Island.[3][7] Before being appointed the Brooklyn Parks Commissioner, Maher served as chief of staff for 18 years in the Parks Department's Brooklyn office.[3] Since assuming the commissioner's office in 2017, Maher has opened and renovated parks throughout Brooklyn.[8]
Maher is a proponent of skateparks and actions sports.[7][10] He believes there should be a skatepark in every community in Brooklyn.[7] As of December 2020, Brooklyn has 15 public skateparks, with 4 additional skateparks in the works.[7] In the late 2010s, Maher worked with a community group in Brownsville, Brooklyn, led by local professional skateboarder Wade Yates, to fund a skatepark built by Spohn Ranch in Betsy Head Park.[11] Maher initiated the Skatefest event series, hosted by the Parks Department.[12][7] Skate Fest II took place at Ocean Hill Playground in Brownsville.[13][10]